Astronomical Institute of the Romanian Academy

Using Berthelot Observatory in remote mode we imaged the first interstellar comet - C/2019 Q4 (Borisov) . Based on the current arc, the comet is on a hyperbolic orbit with an eccentricity of almost 3. The comet will reach perihelion on December 7, 2019. Berthelot Observatory will continue to monitor this objects in the following weeks. Contact: sonka (at) astro.ro.

Romanian Astronomical Journal appears twice a year since 1991 and three times a year since 2015.
This Journal publishes original peer reviewed articles, brief reports, special communications,
theoretical and observational works.
You are invited to submit your original research to roaj.:at:.astro.ro

Ownership and management:
Romanian Astronomical Journal is part of the Romanian Academy series of journals and it is
published in hard copy by the Romanian Academy Publishing House.
Subscription information could be found by contacting the journal at roaj.:at:.astro.ro.
The publication of the online numbers is under the responsibility of the Astronomical Institute of the
Romanian Academy, via the journal webpage

Asteroid (6478) Gault is a mysterious object; although it is in the Main Belt of asteroids, this object presents a cometary activity. During 2018 and 2019 astronomers detected a tail of matter in the asteroid's motion around the Sun, most likely due to the sublimation of light elements in its composition. The phenomenon involves the particles of dust and gas that reflect sunlight.

An international team that includes researchers from MIT-US, Astronomical Institute of the Romanian Academy, Weizmann Institute of Science in Israel, Observatoire de Paris-France, Lowell Observatory, Institute for Astronomy in Hawaii, and Northern Arizona University, has monitored the asteroid and obtained spectral and photometric data of Gault, between March and April 2019.
Near-infrared spectral observations were performed in late March and early April 2019 with the 3 m diameter IRTF (NASA) telescope located in Mauna Kea-Hawaii; the spectral data were corroborated with the photometric data (Figure 1) obtained with the NEEMO-T05 telescope operated by the Astronomical Institute of the Romanian Academy.

Observational data confirm that the surface of the object contains minerals rich in silicium, most likely similar to the mineralogical composition of the asteroid family (25) Phocaea. The spectral data show variations of the spectral slope, decorrelated by a possible burst in object's cometary activity. This aspect can be explained by observing a new layer, unaltered by space weather, predominantly present on the surface of the object after the initial dust layer was entrained in the tail developed by the asteroid.

These results were recently published in the prestigious Astrophysical Journal Letters.

The Sun is the main driver of space weather. Space weather is determining the state of the Earth magnetosphere, which, in its turn, triggers geomagnetic storms.

Coronal mass ejections (CMEs) are pieces of the puzzle that drive space weather. They are one of the most important pieces, because of their large quantities of magnetised plasma released into the heliosphere. An Earth directed CME can hit the magnetosphere about 2-4 days after its initial detection, but not all CMEs arriving to Earth will produce a geomagnetic storm.

Numerous methods (theoretical, numerical and empirical) are being used to predict whether the CME will be geoeffective or not. In a recent paper, a team of researchers lead by D. Beșliu-Ionescu have proposed a new logistic regression model that will produce a probability, expressed as a number between 0 and 1, that a CME will be an event associated with a geomagnetic storm (Beșliu-Ionescu et al., 2019).